When you enter in your self-employment income, TurboTax will determine whether Schedule C or C-EZ needs to be filed. That is all done in the background of the software.
If you do not have a 1099 MISC for your business, these are the steps to enter you self-employment income:
Search for "Schedule C" (as that is just the section name used in the search, but a Schedule C-EZ may still be created) and
then select the Jump to link. This will
take you to where you can enter any cash, personal checks, credit card
payments, or cryptocurrency (Form 1099-K) related to your
self-employment. You may first be asked some general questions about your
business. After you answer them, you’ll be taken to the Let's enter the income for (your line of work) screen where you
can enter this income as Other self-employed
Income. See the sample screenshot below.
See more information below:
https://ttlc.intuit.com/replies/3302098